1. Technical Field
This invention relates generally to cylinder liners used in diesel engines.
2. Related Art
It is common in diesel engines to provide coolant passages between the cylinder block of the engine and its cylinder liners. While proper cooling can preclude excessive distortion of the cylinder liners, particularly in the area of a mounting flange of the liners, and also reduce the wear between the pistons and the liners, such is not easily achieved.
Many cylinder liners used in conventional diesel engines, such as those disclosed in U.S. Pat. No. 5,299,538, have an upper mounting flange that is dimensioned to provide a gap between a perimeter of the mounting flange and the wall of the block. The gap provides for expansion of the mounting flange upon being exposed to heat of combustion. To facilitate cooling of the liner in the region of the upper flange, the bottom side of the flange is brought into fluid contact with liquid coolant that flows through a coolant chamber adjacent the flange. This can lead to liquid coolant leaking past the mounting flange to the upper side of the block or other unintended locations. Also, having a cooling chamber immediately adjacent the mounting flange provides challenges to inhibiting undesirable radial movement of the mounting flange relative to the wall of the cylinder block. Radial movement of the mounting flange typically leads to a reduced life to the cylinder liner.
A cylinder liner for an internal combustion engine comprises a generally cylindrical body having a first dimension and having a flange extending radially outwardly from the first dimension defining a shoulder. The shoulder provides a positive stop in an axial direction against a surface within a cylinder block of the engine. The body has an engagement portion adjacent the shoulder. The engagement portion is necked down from the flange and extends substantially about a circumference of the body. The engagement portion has lower and upper portions providing an interference fit within the cylinder block. The interference fit inhibits fluid flow between the lower and upper portions and the cylinder block where the upper and lower portions engage the cylinder block. The lower and upper portions of the engagement portion are separated from one another by a channel. The channel extends substantially about the circumference of the body and provides a passage for fluid between the lower and upper portions to facilitate cooling of the engagement portion. The upper portion inhibits fluid from contacting the flange while at the same time inhibits radial movement of the flange relative to the cylinder block.
According to another aspect of the invention, a method is provided for replacing a spent cylinder liner in an internal combustion engine. The spent liner is removed from a cylinder block. A new replacement cylinder liner is provided having a flange defining a shoulder and an engagement portion necked down from the flange adjacent the shoulder. The engagement portion extends substantially about a circumference of the replacement liner and comprises lower and upper portions separated from one another by a channel. The channel extends substantially about the circumference of the liner. The replacement liner is pressed into the cylinder block to seat the shoulder of the flange against a stop surface of the cylinder block to limit axial movement of the liner. An interference fit is provided between the lower and upper portions of the engagement portion and the cylinder block at a location spaced below the flange to inhibit radial movement of the liner and to provide a fluid-tight seal for the flow of coolant in the channel.
One advantage of the present invention is providing a cylinder liner that prevents fluid from contacting and thus leaking past a flange of the cylinder liner.
Another advantage of the present invention is that the flange is inhibited from radial movement, thereby reducing the amount of wear to the liner as well as the block counterbore and providing the liner and the block with an extended life in use.